[Fix #111] Fix an incorrect autocorrect for Rails/Presence

[koic]

Fixes #111.

This PR fixes an incorrect autocorrect for Rails/Presence when method arguments of else branch is not enclosed in parentheses.

The following is a reproduction procedure.

% cat example.rb
if value.present?
  value
else
  do_something value
end

% bundle exec rubocop -a --only Rails/Presence
Inspecting 1 file
E

Offenses:

example.rb:1:1: C: [Corrected] Rails/Presence: Use value.presence ||
do_something value instead of if value.present?
  value
else
  do_something value
end.
if value.present? ...
^^^^^^^^^^^^^^^^^
example.rb:1:32: E: Lint/Syntax: unexpected token tIDENTIFIER
(Using Ruby 2.7 parser; configure using TargetRubyVersion parameter,
under AllCops)
value.presence || do_something value
                               ^^^^^

1 file inspected, 2 offenses detected, 1 offense corrected

% cat example.rb
value.presence || do_something value

The auto-corrected code is a syntax error.

% ruby example.rb
example.rb:3: syntax error, unexpected local variable or method,
expecting `do' or '{' or '('
....presence || do_something value

---

Before submitting the PR make sure the following are checked:

• Wrote good commit messages.
• Commit message starts with [Fix #issue-number] (if the related issue exists).
• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• Added tests.
• Added an entry to the Changelog if the new code introduces user-observable changes. See changelog entry format.
• The PR relates to only one subject with a clear title
  and description in grammatically correct, complete sentences.
• Run bundle exec rake default. It executes all tests and RuboCop for itself, and generates the documentation.